In general, a circuit board for typical electronic devices includes different card-edge connectors that provide slot connection for various modular electronic cards. Electrical contacts on a front edge of these cards make electrical contact with corresponding conductive terminals on the card-edge connectors to complete electrical conduction between the electronic cards and the main circuit board.
For known card-edge connectors, the connection between conductive terminals and the insulative housing is generally made by inserting conductive terminals of various sizes into a plurality of receiving passageways arranged alternately in a top-down sequence on a side surface of the insulative housing. The main circuit board is provided with a corresponding number of receiving passageways for the conductive terminals so that the conductive terminals can be inserted and soldered in the receiving passageways. Consequently, electrical conduction between the electronic cards and the main circuit board can be achieved. As the conductive terminals of various sizes are inserted to the receiving passageways, arranged alternately in a top-down sequence on the side surface of the insulative housing, the addition of conductive terminals that connect the electronic card with the main circuit board requires increased thickness of the insulative housing and the number of rows of receiving passageways arranged in an alternating pattern and the receiving passageways on the main circuit board. The section between any two receiving passageways is rather small, thus the layout of the circuit is designed to permit only one wire to pass through the section. Accordingly, the number of layers of a circuit needs to be increased when the number of receiving passageways increases. For example, a four-layer layout is required for four rows of receiving passageways. Such a configuration not only incurs higher costs but also increases the thickness of the insulative housing, taking up much of the overall space. Therefore, a need exists in the art to deal with the higher costs incurred by the increased number of receiving passageways on the main circuit board and the increased thickness caused by the combination of the conductive terminals within the insulative housing, thereby the space of an electronic device can be managed efficiently and the costs can be reduced as well.